It is picking up a signal from one of the wheel sensors probably.
Go here to read files on ABS issues
- Anti-Lock Brake Warning Indicator Always On
- Hydraulic solenoid relay.
- Hydraulic pump motor relay.
- Brake anti-lock sensor(s).
- Hydraulic anti-lock actuator assembly.
- Anti-lock brake control module.
QT5 PERFORM ABS TROUBLE CODE RETRIEVAL
NOTE: The first code to flash will be the start code (12). Also, each code is repeated three times before proceeding to the next trouble code.
- Key OFF.
- Jump Pin 4 of the data link connector to ground.
- Key ON.
- Observe the anti-lock brake warning indicator.
Does the anti-lock brake warning indicator flash codes?
RECORD code(s). GO to the following ABS Trouble Code Identification Chart in this section and PERFORM Pinpoint Test specified for first code retrieved.
If indicator is illuminated constantly, GO to Pinpoint Test D1
If indicator is not illuminated, GO to Pinpoint Test A1